Endoscope having a guide tube

ABSTRACT

An endoscope having a guide tube is described herein. The assembly has an endoscope which is slidably insertable within the lumen of a guide tube. The guide tube is configured to be rigidizable along its entire length from a relaxed configuration. The endoscope has a steerable distal portion to facilitate the steering of the device through tortuous paths. In the relaxed configuration, a portion of the guide tube is able to assume the shape or curve defined by the controllable distal portion of the endoscope. Having assumed the shape or curve of the endoscope, the guide tube may be rigidized by the physician or surgeon to maintain that shape or curve while the endoscope is advanced distally through the tortuous path without having to place any undue pressure against the tissue walls.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 10/139,289filed May 2, 2002, which is a continuation-in-part of U.S. patentapplication Ser. No. 09/969,927 filed Oct. 2, 2001, which is acontinuation-in-part of U.S. patent application Ser. No. 09/790,204filed Feb. 20, 2001, which claims priority of U.S. Provisional PatentApplication Ser. No. 60/194,140 filed Apr. 3, 2000, each of which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to endoscopes and endoscopicmedical procedures. More particularly, it relates to a method andapparatus to facilitate insertion of a flexible endoscope along atortuous path using a guide tube apparatus, such as for colonoscopicexamination and treatment.

BACKGROUND OF THE INVENTION

An endoscope is a medical instrument for visualizing the interior of apatient's body. Endoscopes can be used for a variety of differentdiagnostic and interventional procedures, including colonoscopy,bronchoscopy, thoracoscopy, laparoscopy and video endoscopy.

Colonoscopy is a medical procedure in which a flexible endoscope, orcolonoscope, is inserted into a patient's colon for diagnosticexamination and/or surgical treatment of the colon. A standardcolonoscope is typically 135-185 cm in length and 12-19 mm in diameter,and includes a fiberoptic imaging bundle or a miniature camera locatedat the instrument's tip, illumination fibers, one or two instrumentchannels that may also be used for insufflation or irrigation, air andwater channels, and vacuum channels.

The colonoscope is inserted via the patient's anus and is advancedthrough the colon, allowing direct visual examination of the colon, theileocecal valve and portions of the terminal ileum. Insertion of thecolonoscope is complicated by the fact that the colon represents atortuous and convoluted path. Considerable manipulation of thecolonoscope is often necessary to advance the colonoscope through thecolon, making the procedure more difficult and time consuming and addingto the potential for complications, such as intestinal perforation.

Steerable colonoscopes have been devised to facilitate selection of thecorrect path though the curves of the colon. However, as the colonoscopeis inserted farther and farther into the colon, it becomes moredifficult to advance the colonoscope along the selected path. At eachturn, the wall of the colon must maintain the curve in the colonoscope.The colonoscope rubs against the mucosal surface of the colon along theoutside of each turn. Friction and slack in the colonoscope build up ateach turn, making it more and more difficult to advance and withdraw thecolonoscope. In addition, the force against the wall of the colonincreases with the buildup of friction. In cases of extreme tortuosity,it may become impossible to advance the colonoscope all of the waythrough the colon.

Steerable endoscopes, catheters and insertion devices for medicalexamination or treatment of internal body structures are described inthe following U.S. patents, the disclosures of which are herebyincorporated by reference in their entirety: U.S. Pat. No. 4,543,090;4,753,223; 5,337,732; 5,337,733; 5,383,852; 5,487,757 and 5,662,587.

BRIEF SUMMARY OF THE INVENTION

An endoscopic assembly and method of advancing the assembly which isable to traverse tortuous paths, such as the colon, without excessivelycontacting the walls of the colon is described herein. The assemblygenerally comprises a combination of an endoscope which is slidablyinsertable within the lumen of a guide tube. The endoscope may be anyconventional endoscope having a shaft which extends from a handle. Thedistal end of the shaft preferably comprises a controllable distalportion which may be manipulated to facilitate the steering of theassembly through the tortuous path. The guide tube may be a conventionalflexible conduit which is configured to be rigidizable along its entirelength from a relaxed configuration. In the relaxed configuration, aportion of the guide tube is able to assume the shape or curve definedby the controllable distal portion of the endoscope. Having assumed theshape or curve of the endoscope, the guide tube may be rigidized by thephysician or surgeon to maintain that shape or curve.

Alternatively, the guide tube may also be used with an endoscope havingan automatically controlled proximal portion and a selectively steerabledistal portion. Such a controllable endoscope may have a distal portionwhich is manually steerable by the physician or surgeon to assume ashape to traverse an arbitrary curved path and a proximal portion whichis automatically controlled by, e.g., a computer, to transmit theassumed shape along the proximal portion as the endoscope is advanced orwithdrawn. More detailed examples are described in copending U.S. patentapplication Ser. No. 09/969,927, which has been incorporated above byreference in its entirety.

The guide tube may be comprised of a plurality of individual segmentswhich are linked adjacent to one another via one or more tensioningwires or elements. These tensioning elements may be placedcircumferentially about each of the segments and preferably runthroughout the length of the guide tube through each of the individualsegments. When the guide tube is to be rigidized, the tensioningelements may be pulled or tightened to draw the segments together suchthat the entire guide tube becomes rigid. The tensioning elements maythen be loosened such that the individual segments may move relative toone another.

In use, e.g., in the colon, the physician or surgeon may typically firstadvance the distal portion of the endoscope within the body of thepatient. When the first curve of the colon is approached, the user mayappropriately steer the distal portion of the endoscope to assume acurve for traversing the path. At this point, the endoscope ispreferably held stationary relative to the patient while the guide, in arelaxed and flexible state, is advanced over the shaft of the endoscopeuntil the distal end of the guide tube is at, or a short distance past,the distal tip of the endoscope. Once the guide tube, or at least itsdistal portion, has assumed the curve formed by the controllable distalportion of the endoscope, the guide tube may then be rigidized,preferably along its length, to hold its assumed shape. Once this isdone, the endoscope may be further advanced within the rigidized guidetube to traverse the curved pathway without having to place any pressureagainst the walls of the colon. The steps for advancing the endoscopemay be repeated as necessary until the desired area within the body hasbeen reached.

At any point during the exploratory procedure, the guide tube may beremoved from the colon while leaving the endoscope behind. To remove theassembly from the colon, the guide tube may first be withdrawn and theendoscope may be subsequently withdrawn. Alternatively, the above stepsmay be repeated in reverse order to withdraw both the guide tube and theendoscope from the region.

The outer surface of the guide tube preferably has a tubular coveringwhich covers at least a majority of the tube to prevent the entry ofdebris and fluids within the lumen of the guide tube between theindividual segments. The covering also facilitates the advancement andwithdrawal of the guide tube by preventing tissue from being pinchedbetween the segments. To prevent tissue from being pinched between theguide tube and endoscope during assembly movement, expandable bellows oran additional covering may optionally be placed over the distal openingof the guide tube. This additional covering may simply be an integralextension of the covering over the surface of the guide tube, or it maybe a separate covering attached to the distal end of the guide tube.This covering may also be attached to or near the distal end of theendoscope to maintain a seal between the endoscope shaft and the guidetube. The coverings and their variations may be attached by anyconventional method as practicable. If the covering over the distal endof the guide tube is utilized, as the distal portion of the endoscopeshaft is advanced distally through the guide tube, the coveringpreferably expands distally along with the endoscope or simply slidesdistally along with the endoscope. When the shaft is retracted withinthe guide lumen, the. covering again preferably retracts proximallyalong with the proximal movement of the distal end of the endoscope orit may simply be retracted manually along with the endoscope. The use ofthe additional covering may also aid in maintaining the sterility of theinternal lumen of the guide tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a variation of the guide tube assembly in which anendoscope is pushed through and supported by a guide tube.

FIG. 2 shows a cross-sectional view of the guide tube assembly of FIG.1.

FIG. 3 shows the guide tube variation of FIG. 1 with a portion of thetube partially removed for clarity.

FIG. 4A shows a variation on a steerable endoscope having a selectivelysteerable distal portion and an automatically controllable proximalportion which may be used with the rigidizable guide tube.

FIG. 4B shows a variation of the guide tube assembly showing a handle.

FIG. 5 shows a wire frame model of a section of the automaticallycontrollable endoscope traversing an arbitrary curve.

FIG. 6A shows a variation in which the distal end of the endoscoperemains unattached to the flexible covering.

FIG. 6B shows another variation in which the distal end of the endoscopeis attached to the flexible covering.

FIG. 7 shows the distal end of the endoscope extending past the distalend of the guide tube and the flexible covering extending distally alongwith the endoscope.

FIG. 8A shows another variation in which the covering is configured asan elastic tubular structure.

FIG. 8B shows another variation in which the covering is configured asan elastic diaphragm structure.

FIG. 9 shows the variations of FIGS. 8A and 8B in which the endoscope isextended distally.

FIG. 10 shows yet another variation in which a plastic covering is usedto cover the endoscope and guide tube.

FIGS. 11A to 11E show a variation on advancing an endoscope through acolon using the guide tube as support.

FIG. 12 shows a variation in which the guide tube may be withdrawn fromthe colon while leaving the endoscope behind.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a representative illustration of a variation onguide tube assembly 10 is seen partially disassembled for clarity.Assembly 10 generally comprises an endoscope 12 which is insertablewithin guide tube 14 through guide lumen 16. Endoscope 12 may be anyconventional type endoscope having a handle 18 with shaft 20 extendingtherefrom. The distal end of shaft 20 preferably comprises acontrollable distal portion 22 which may be manipulated to facilitatethe steering of the device through the body. Endoscope shaft 20 may beslidingly disposed within guide lumen 16 such that controllable distalportion 22 is able to be passed entirely through guide tube 14 and outdistal opening 24 defined at the distal end of tube 14.

Alternatively, guide tube 14 may also be used with an endoscope havingan automatically controlled proximal portion and a selectively steerabledistal portion, as described in further detail below. Such acontrollable endoscope may have a distal portion which is manuallysteerable by the physician or surgeon to assume a shape to traverse anarbitrary curved path and a proximal portion which is automaticallycontrolled by, e.g., a computer, to transmit the assumed shape along theproximal portion as the endoscope is advanced or withdrawn. Moredetailed examples are described in copending U.S. patent applicationSer. No. 09/969,927, which has been incorporated above by reference inits entirety.

One example of such an endoscope is shown in FIG. 4A, which shows onevariation of steerable endoscope 80. Endoscope 80 has an elongate body82 with a manually or selectively steerable distal portion 84 and anautomatically controlled proximal portion 86. The selectively steerabledistal portion 84 can be selectively steered or bent up to a full 180°bend in any direction. A fiberoptic imaging bundle 92 and one or moreillumination fibers 94 may extend through body 82 from proximal end 90to distal end 88. Alternatively, endoscope 80 may be configured as avideo endoscope with a miniaturized video camera, e.g., a CCD camera,positioned at distal end 88 of endoscope body 82. The images from thevideo camera may be transmitted to a video monitor by a transmissioncable or by wireless transmission where images may be viewed inreal-time or recorded by a recording device onto analog recordingmedium, e.g., magnetic tape, or digital recording medium, e.g., compactdisc, digital tape, etc. Optionally, body 82 of endoscope 80 may includeone or two instrument channels 96, 98 that may also be used forinsufflation or irrigation, air and water channels, vacuum channels,etc. Body 82 of endoscope 80 is preferably highly flexible so that it isable to bend around small diameter curves without buckling or kinkingwhile maintaining the various channels intact. When configured for useas a colonoscope, body 82 of the endoscope 80 may range typically from135 to 185 cm in length and approximately 12-13 mm in diameter.Endoscope 80 can be made in a variety of other sizes and configurationsfor other medical and industrial applications.

A proximal handle 100 is attached to proximal end 90 of elongate body82. Handle 100 may include ocular 104 connected to fiberoptic imagingbundle 92 for direct viewing and/or for connection to a video camera 106or a recording device 108. Handle 100 may be connected to anillumination source 110 by illumination cable 116 that is connected toor continuous with illumination fibers 94. A first luer lock fitting 112and a second luer lock fitting 114 on the handle 100 may be connected toinstrument channels 96, 98.

Handle 100 may be connected to an electronic motion controller 122 byway of controller cable 118. Steering control 102 may be connected toelectronic motion controller 122 by way of a second cable 120. Steeringcontrol 102 may allow the user to selectively steer or bend selectivelysteerable distal portion 84 of body 82 in the desired direction.Steering control 102 may be a joystick controller as shown, or otherknown steering control mechanism. Electronic motion controller 122 maycontrol the motion of automatically controlled proximal portion 86 ofbody 82. The electronic motion controller 122 may be implemented using amotion control program running on a microcomputer or using anapplication-specific motion controller. Alternatively, electronic motioncontroller 122 may be implemented using, a neural network controller.

An axial motion transducer 124 may be provided to measure the axialmotion of the endoscope body 82 as it is advanced and withdrawn. Theaxial motion transducer 124 can be made in many possible configurations.By way of example, the axial motion transducer 124 in FIG. 4A isconfigured as a ring 126 that may entirely or partially surround body 82of endoscope 80. The axial motion transducer 124 is preferably attachedto a fixed point of reference, such as the surgical table or theinsertion point for endoscope 80 on the patient's body. As body 82 ofendoscope 80 slides through axial motion transducer 124, it produces asignal indicative of the axial position of endoscope body 82 withrespect to the fixed point of reference and sends a signal to electronicmotion controller 122 by telemetry or by a cable (not shown). Axialmotion transducer 124 may use optical, electronic or mechanical methodsto measure the axial position of endoscope body 82. Other possibleconfigurations for the axial motion transducer 124 are further describedin copending U.S. patent application Ser. No. 09/969,927.

FIG. 5 shows a wire frame model of a section of body 82 of endoscope 80in a neutral or straight position. Most of the internal structure ofendoscope body 82 has been eliminated in this drawing for the sake ofclarity. Endoscope body 82 is divided up into segments or sections 1, 2,3, . . . , etc. The geometry of each segment is defined by four lengthmeasurements along the a, b, c and d axes and each of the adjacentsegments are preferably interconnected via joints which allow theindependent angular movement and/or rotation of each segment relative toone another. For example, the geometry of segment 1 is defined by thefour length measurements l_(1a), l_(1b), l_(1c), l_(1d), and thegeometry of segment 2 is defined by the four length measurements l_(2a),l_(2b), l_(2c), l_(2d), etc. Each adjacent segment 1, 2, 3, . . . ,etc., are preferably individually controlled by linear actuators (notshown), e.g., electric, pneumatic, hydraulic, etc. motors. The linearactuators may utilize one of several different operating principles. Forexample, to bend the endoscope body 82 in the direction of the a axis,the measurements l_(1a), l_(2a), l_(3a) . . . l_(10a) can be shortenedand the measurements l_(1b), l_(2b), l_(3b) . . . l_(10b) would belengthened an equal amount. The amount by which these measurements arechanged determines the radius of the resultant curve. Alternatively,individual motors may be actuated to move adjacent segments relative toone another to effect a resultant curvature, as described in furtherdetail in U.S. patent application Ser. No. 09/969,927.

In the automatically controlled proximal portion 86, each segment may beautomatically controlled by electronic motion controller 122, which usesa curve propagation method to control the shape of endoscope body 82.Endoscope body 82 has been maneuvered through the curve in colon C withthe benefit of selectively steerable distal portion 84 and nowautomatically controlled proximal portion 86 resides in the curve. Whenendoscope body 82 is advanced distally by one unit, segment 1 moves intothe position marked 1′, segment 2 moves into the position previouslyoccupied by segment 1, segment 3 moves into the position previouslyoccupied by segment 2, etc. The axial motion transducer 124 produces asignal indicative of the axial position of endoscope body 82 withrespect to a fixed point of reference and sends the signal to theelectronic motion controller 122, under control of the electronic motioncontroller 122, each time endoscope body 82 advances one unit, eachsegment in automatically controlled proximal portion 86 is signaled toassume the shape of the segment that previously occupied the space thatit is now in. Thus, the curve propagates proximally along the length ofautomatically controlled proximal portion 86 of endoscope body 82. Thecurve appears to be fixed in space, as endoscope body 82 advancesdistally.

Similarly, when the endoscope body 82 is withdrawn proximally, each timeendoscope body 82 is moved proximally by one unit, each segment inautomatically controlled proximal portion 86 is signaled to assume theshape of the segment that previously occupied the space that it is nowin. The curve propagates distally along the length of the automaticallycontrolled proximal portion 86 of endoscope body 82, and the curveappears to be fixed in space, as endoscope body 82 withdraws proximally.Whenever endoscope body 82 is advanced or withdrawn, axial motiontransducer 124 preferably detects the change in position and electronicmotion controller 122 propagates the selected curves proximally ordistally along automatically controlled proximal portion 86 of endoscopebody 82 to maintain the curves in a spatially fixed position. Thisallows endoscope body 82 to move through tortuous curves without puttingunnecessary force on the walls of colon C.

One example of using assembly 10, e.g., in the colon, the physician orsurgeon may typically first advance distal portion 22 of endoscope 12within the body of the patient. Upon reaching the first point at whichendoscope 12 requires steering to negotiate a curved pathway, the usermay appropriately steer distal portion 22 to assume a curve fortraversing the pathway. At this point with endoscope 12 held stationaryrelative to the patient, guide tube 14 may be advanced over shaft 20until the distal end of guide tube 14 is at, a short distance before, ora short distance past, the distal tip of controllable distal portion 22.The short distance is considered to range anywhere from a fewcentimeters to several inches. While guide tube 14 is advanced overshaft 20, tube 14 is preferably in a non-rigid state and is flexibleenough to assume the curve formed by controllable distal portion 22.

Once tube 14, or at least its distal portion, has assumed the curveformed by controllable distal portion 22, tube 14 is rigidizedpreferably along its length to hold its assumed shape. Once this isaccomplished, shaft 20 of endoscope 12 may be further advanced withinthe rigidized guide tube 14 to traverse the curved pathway withouthaving to place any pressure against the walls of the colon.

Alternatively, if automatically controllable endoscope 80 is utilized,it may generally be used in the same manner as conventional endoscope12. However, because endoscope body 82 is automatically controllableeither along its entire length or along several segments proximally ofsteerable distal portion 84, the steerable distal portion 84 may beadvanced farther past the distal end of guide tube 14 than might bepossible with conventional endoscope 12. Controllable endoscope 80 maybe used in all other aspects similarly as conventional endoscope 12 asdescribed herein.

Returning to FIG. 1, bellows or covering 26 may cover distal opening 24of guide tube 14 to prevent the entry of debris and fluids within guidelumen 16. As distal portion 22 of shaft 20 is advanced distally throughtube 14 and out of guide lumen 16, covering 26 is preferably configuredto expand distally either over or with shaft 20 while maintaining a sealwith guide lumen 16. When shaft 20 is retracted within guide lumen 16 orwhen guide tube 14 is advanced distally relative to shaft 20, covering26 is preferably configured to retract proximally back over distalopening 24 along with the proximal movement of distal portion 22. Theuse of covering 26 is optional and may be used to maintain the sterilityof guide lumen 16. Covering 26 may also be used to prevent the pinchingand tearing of tissue when shaft 20 is withdrawn within guide lumen 16.

Guide tube 14 may be any conventional appropriately flexible conduitwhich is capable of being rigidized along its entire length. Thevariation shown in FIG. 1 is comprised of a plurality of individualsegments 28 which are linked adjacent to one another via several, i.e.,more than one, tensioning wires or elements 30. Segments 28 may be aseries of interconnecting ball-and-socket type segments which allowadjacent segments 28 to angularly pivot relative to one another to forman angle for traversing curves. These segments 28 may be rigidized viatensioning elements 30 which may be placed circumferentially aboutsegments 28, as shown in FIG. 2, which is a cross-sectioned view ofassembly 10 from FIG. 1. In this variation, there are four tensioningwires 30A, 30B, 30C, 30D which are each placed 90° relative to oneanother. Although four wires are shown in this example, a fewer numberof wires may also be used, e.g., three wires. Each of these wires 30A,30B, 30C, 30D may be routed through an integral channel or lumen definedin the walls of each segment 28. Moreover, they may be individuallymanipulated or they may all be manipulated simultaneously to effect atensioning force for either rigidizing or relaxing guide tube 14 alongits length.

FIG. 2 also shows the relative positioning of shaft 20 in relation tosegment 28. As seen, shaft 20, which may contain any number of channels34 for illumination fibers, optical fibers, etc., and working channels34, is slidingly disposed within guide lumen 16. This variation shows agap separation between the outer surface of shaft 20 and the innersurface of segment 28. This gap may vary depending upon the diameter ofthe endoscope being used and the desired cross-sectional area of guidetube 14, but a nominal separation is preferable to allow the uninhibitedtraversal of shaft 20 within guide lumen 16. An example of a rigidizableconduit structure which may be utilized as part of the present inventionis shown and described in further detail in U.S. Pat. No. 5,251,611 toZehel et al., which is incorporated herein by reference in its entirety.

Referring to FIG. 4B, a preferred embodiment of the invention, aflexible steerable exploratory device, generally 401 is shown, whichincludes an inner flexible conduit, generally 410, which may be maderigid along its entire length, and shall be described in greater detailsubsequently. The conduit 410 is threaded through an outer flexibleconduit or similar tube 411, which, when relaxed, is sufficientlyflexible to yield to forces within the gut or other cavity through whichthe device is inserted. Suitable materials of construction for thisconduit include, by way of example, but not limitation, NEOPRENE,natural rubber, plastic, stainless steel, etc. The conduit preferablyhas an outside diameter suitable for use in the human gut, althoughother diameters could be employed depending on the end use and thestiffness of material of construction of the conduit 411.

The device 401 as illustrated in FIG. 4B has a distal end, generally412, which is preferably flexible with respect to the flexible conduit411 and may house an instrument port 412 a for harvesting tissue samplesand/or a vision aperture for relaying video transmissions, for example.As the device preferably has fiber-optic capability, fiber-optic fibersmay be run through the flexible conduit 411. Other possible uses of thedistal end 412 of the device 401 include containment of surgical cuttingtools, lasers, vascular catheters, angioscopes, illuminating devices,clip and ligature devices and ultra-sound and dissecting devices and thelike.

The flexible device 401 also has a proximal end, generally 413, whichpreferably contains a controller 414 for manipulating and steering theflexible distal end 412. The proximal end 413 also preferably contains aconduit advance/retreat controller, generally 415 and a conduitstiffen/relax controller, generally 416.

The controllers 414-416 may be commercially-available servo-motordriven, and/or pneumatically or hydraulically operated controllers. Itis additionally possible to equip the controllers 414-416 with voiceactivation. Thus, the device 401 and in particular the distal end 412thereof is a “smart” instrument, in that it may be guided by a joystick, voice activation, “lock-on device,” or laser or infra-redguidance system. A video screen may also be used to assist in guidingthe device.

As illustrated in FIG. 4B, the flexible exploratory device 401 includeswithin the outer flexible conduit 411 a passageway 417 through which theinner flexible conduit 410 is slidably disposed and free to travel. Therelative size of the passageway 417 and conduit 410 is not critical,provided there is sufficient space to allow the inner conduit 410 andouter conduit 411 to slide relative to one another, yet not so muchspace as to permit the relaxed inner conduit 410 to buckle or bendappreciably when slid through the outer conduit

In addition to providing sufficient space for the inner flexible conduit410 to slide within the outer flexible conduit 411, the annular space409 between the inner wall of the conduit 411 and the outer wall of theinner flexible conduit 410 preferably provides sufficient room fordeployment of, for example, additional functional devices, such aselectrical wiring, optical fibers and the like which may be used at thedistal end 412 of the device.

The outer surface of guide tube 14 preferably has a tubular covering 32which covers at least a majority of tube 14. Tubular covering 32 mayprovide a barrier between the debris and fluids of the body environmentand the interior guide lumen 16, if also used with covering 26.Moreover, covering 26 may be an integral extension of tubular covering32 and may accordingly be made from a continuous layer of material.Tubular covering 32 may also provide a lubricous cover to facilitate theinsertion and movement of guide tube 14 along the walls of the bodylumen as well as to provide a smooth surface inbetween the individualsegments 28 to prevent the tissue from being pinched or trapped. Tubularcovering 32 may be made from a variety of polymeric materials, e.g.,PTFE, FEP, Tecoflex, etc.

FIG. 3 shows a side view of guide tube variation 14 with a portion ofthe wall partially removed for clarity. As shown, individual segments 28are aligned adjacent to one another with interconnecting sleeves 40placed inbetween. Sleeves 40, in this variation, may be used to providea pivoting structure to allow guide tube 14 to flex into differentpositions. Alternatively, segments 28 may be curved ball-and-socket typejoints configured to interfit with one another. Tubular covering 32 mayalso be seen to cover at least the majority of guide tube 14.Optionally, a distal end portion of guide tube 14 may be configured tobe controllable such that guide tube 14, like the controllable distalportion 22 of the endoscope 12, may define an optimal path fortraversal.

Bellows or covering 26 may optionally be appended to the distal end ofconventional endoscope shaft 20 or controllable shaft 82. Throughout thedescription herein, automatically controllable endoscope 82 may beinterchanged with conventional endoscope 12 when used in guide tube 14as well as with the use of bellows or covering 26. Although descriptionson the method of use may describe use with conventional endoscope 12,this is done for brevity and is not intended to be limiting. Thedescription is intended to apply equally to use with controllableendoscope 80 since the two may be easily interchanged depending upon thedesired use and result. FIG. 6A shows one variation in which shaft 20 or80 is unattached to covering 26 such that endoscope 12 may be freelyinserted and withdrawn from guide lumen 16. Covering 26 may be omittedaltogether from the assembly but is preferably used not only to helpmaintain an unobstructed guide lumen 16, but also to prevent the wallsof the body lumen from being pinched between the endoscope shaft 20 or80 and guide tube 14 during advancement of the assembly. As seen in FIG.6A, covering 26 may be separately attached at attachment region 50 tothe outer surface or distal edge of guide tube 14. Covering 26 may alsofurther comprise a gusseted region 52 which allows the covering 26 to becompressed into a small compact profile and expanded much like a bellowsduring shaft 20 or 80 advancement. When shaft 20 or 80 is withdrawn,gusseted region 52 may allow covering 26 to recompress or reconfigureitself back into its compacted shape. In this variation, covering 26 isunattached to shaft 20 or 80; therefore, once the assembly has reached apredetermined location within the colon, covering 26 may be removedthrough a working channel within endoscope 12 or the working tools maysimply be pierced through covering 26, although this is less preferable,before a procedure may be begin.

FIG. 6B shows another variation where covering 26 may be attached to theendoscope shaft 20 or 80 near or at the distal end of controllabledistal portion 22 along attachment region 54. As shaft 20 or 80 isadvanced or withdrawn from guide lumen 16, covering 26 remains attachedto the endoscope 12. FIG. 7 shows shaft 20 or 80 being advanced to adistal position through guide lumen 16. As shaft 20 or 80 is advanced,gusseted region 52 may be seen expanding to accommodate the distalmovement. The gusseted region 52 may be configured to allow shaft 20 or80 to be advanced to any practical distance beyond guide tube 14, e.g.,a few or several inches, depending upon the application. With thisvariation, shaft 20 or 80 may be extended through guide lumen 16 to thisdistal position prior to first advancing shaft 20 or 80 within the colonof a patient as well as to allow enough room so that the controllabledistal portion 22 may have enough space to be manipulated to assume adesired shape or curve over which guide tube 14 may be advanced over.

Another variation is shown in FIG. 8A in which covering 60 may beconfigured as an elastic tubular member. As seen, when endoscope shaft20 or 80 is in a retracted position, covering 60 may be configured toform a tubular structure when relaxed. As endoscope shaft 20 or 80 isadvanced distally, as seen in FIG. 9, covering 60 may stretch along withshaft 20 or 80 to maintain the sterility of guide lumen 16.

Yet another variation is shown in FIG. 8B in which covering 62 may beconfigured as an elastic rolling diaphragm. When endoscope shaft 20 or80 is retracted, covering 62 may be configured to evert upon itself suchthat part of covering 62 may be pulled proximally into guide lumen 16.Such a covering 62 material may comprise any number of elastomers,elastomeric materials, or rubber-type materials, e.g., neoprene orlatex. When endoscope shaft 20 or 80 is advanced distally, covering 62may likewise revert and stretch distally along with shaft 20 or 80, alsoas shown in FIG. 9.

Alternatively, the covering may simply be a plastic covering or wrapper64 which is non-elastic, as shown in FIG. 10. Such coverings 64 areconventionally available and may be advanced along with endoscope shaft20 or 80 and retracted likewise as endoscope shaft 20 or 80 isretracted.

FIGS. 11A to 11E show one variation of advancing a conventionalendoscope 12 using the guide tube 14. FIG. 11A shows an illustrativecolon C of a patient. Endoscope 12 may be inserted within colon Cthrough the anus A of the patient. As the distal portion 22 is advancedthrough rectum R, it encounters its first point of curvature. Here,controllable distal portion 22 may be manipulated much as a conventionalendoscope to select an optimal path into sigmoid colon S. The optimalpath is one which presents the most efficient path for advancingendoscope 12 with the least amount of contact against the walls of colonC.

Once distal portion 22 has been manipulated to select the appropriateshape, guide tube 14 may be advanced through anus A and rectum R overendoscope 12 while endoscope 12 is maintained stationary relative tocolon C. Guide tube 14 is preferably in a relaxed state and is able toconform easily to the shape defined by controllable distal portion 22.Guide tube 14 may be advanced to the distal end of distal portion 22, ashort distance before, or a short distance past the distal end ofportion 22, as shown in FIG. 11B. Once guide tube 14 has been advanceddistally, it may be rigidized along its length such that it maintainsthe shape defined by endoscope 12.

Then, with guide tube 14 rigidized, it is preferably held stationaryrelative to colon C while endoscope 12 is further advanced through guidetube 14 until distal portion 22 reaches the next point of curvature.Controllable distal portion 22 may then be manipulated to select anoptimal path into descending colon D, as shown in FIG. 11C. Once theoptimal path has been selected, endoscope 12 is preferably maintainedstationary relative to colon C while guide tube 14 is placed into itsrelaxed state and advanced over endoscope 12. Guide tube 14 may beadvanced distally until the distal end of endoscope 12 is reached, asshown in FIG. 11D. At this point, guide tube 14, having assumed theshape defined by controllable distal portion 22, may be rigidized alongits length to maintain this shape. Endoscope 12 may then be advanceddistally again, as seen in FIG. 11E, while using the rigidized guidetube 14 to provide the column strength to advance endoscope 12 withoutthe need to unnecessarily contact the walls of colon C. Endoscope 12 maybe advanced until distal portion 22 reaches the flexure betweendescending colon D and transverse colon T. Once this point is reached,the steps described above may be repeated as necessary until endoscope12 has negotiated its way through transverse colon T, and ascendingcolon G until cecum E has been reached, or until a desired locationwithin colon C has been reached.

At any point during the exploratory procedure, guide tube 14 may beremoved from colon C while leaving endoscope 12 behind, as shown in FIG.12 by tube withdrawal 70. If endoscope 12 were left within colon C, theendoscope 12 may be used and manipulated as any conventional endoscopeor colonoscope would be during a conventional colonoscopy examination.Guide tube 14 may also be partially retracted to allow the distalportion 22 to be steered or manipulated to examine or treat the colon Cwhile still providing support and guidance to the proximal scope sectionof endoscope 12. To remove the assembly from colon C, guide tube 14 mayfirst be withdrawn, as shown, and endoscope 12 may be subsequentlywithdrawn. Alternatively, the above steps may be repeated in reverseorder to withdraw both guide tube 14 and endoscope 12 from colon C.

The applications of the guide tube system and methods of use discussedabove are not limited to regions of the body but may include any numberof further treatment applications. Other treatment sites may includeareas or regions of the body around organ bodies. Additionally, thepresent invention may be used in other environments which presenttortuous paths such as exploratory procedures on piping systems, ducts,etc. Moreover, various other rigidizable guide tube apparatus andapplications may be utilized beyond what is described herein.Modification of the above-described assemblies and methods for carryingout the invention, and variations of aspects of the invention that areobvious to those of skill in the art are intended to be within the scopeof the claims.

1-21. (canceled)
 22. Apparatus for advancing a first diagnostic ortherapeutic instrument into a hollow body organ of unsupported anatomy,the apparatus comprising: a handle; an overtube coupled to the handle,the overtube having a elongated portion, a distal region, a distalopening and a lumen extending therethrough to permit passage of a firstdiagnostic or therapeutic instrument; an atraumatic tip disposed on thedistal region adjacent to the distal opening, wherein the atraumatic tipdeflects the hollow body organ in the vicinity of the distal opening sothat tissue is not caught or pinched when the first diagnostic ortherapeutic instrument is translated through the distal opening.
 23. Theapparatus of claim 22 wherein the overtube includes means for lockingthe overtube in a bent configuration.
 24. The apparatus of claim 23wherein the means for locking the overtube in a bent configurationcomprises: a plurality of links, each link having a bore that definesthe lumen of the overtube; and means for applying a clamping load to theplurality of links.
 25. The apparatus of claim 22 wherein the firstdiagnostic or therapeutic instrument has a steerable distal tip, and thedistal region of the overtube comprises a flexible material deflectableby the steerable distal tip of the first diagnostic or therapeuticinstrument.
 26. A method for advancing a first diagnostic or therapeuticinstrument having a steerable distal tip into an unsupported, hollowbody organ, the method comprising: providing an apparatus having ahandle and an overtube coupled to the handle, the overtube comprising anelongated portion having a distal opening and a lumen extendingtherethrough to permit passage of the first diagnostic or therapeuticinstrument, and an atraumatic tip disposed adjacent the distal opening;inserting the apparatus with the first diagnostic or therapeuticinstrument into the unsupported, hollow body organ; and deflecting thehollow body organ with the atraumatic tip so that tissue is not caughtor pinched when the first diagnostic or therapeutic instrument istranslated through the distal opening.
 27. The method of claim 26further comprising: locking the overtube in a bent configuration; andadvancing the first diagnostic or therapeutic instrument through thelumen of the overtube in the bent configuration.
 28. The method of claim27 wherein providing an apparatus comprises providing an apparatuswherein the overtube comprises a plurality of links, each link having abore that defines the lumen of the overtube, and locking the overtube ina bent configuration comprises applying a clamping load to the pluralityof links.